<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>标题</title>
		<script type="text/javascript">
			(function(doc, win) {
				var docEl = doc.documentElement,
					resizeEvt = "orientationchange" in window ? "orientationchange" : "resize",
					recalc = function() {
						var clientWidth = docEl.clientWidth;
						if (!clientWidth) {
							return
						}
						if (clientWidth >= 750) {
							docEl.style.fontSize = "100px"
						} else {
							docEl.style.fontSize = 100 * (clientWidth / 750) + "px"
						}
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				if (!doc.addEventListener) {
					return
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				win.addEventListener(resizeEvt, recalc, false);
				doc.addEventListener("DOMContentLoaded", recalc, false)
			})(document, window);
		</script>
		<style type="text/css">
			h1 {
				font-size: .4rem;
			}
		</style>
	</head>
	<body>
		<h1>我的标题</h1>
		<a href="#">我的链接</a>
	</body>
</html>
